VMware Backup – Changed Block Tracking

Vembu VMBackup utilizes VMware CBT (Changed Block Tracking) feature to help backing up only the modified blocks of a virtual disk rather than backing up an entire disk for each incremental backup job. This saves more storage space, time and lowers the bandwidth utilization from being over-consumed through incremental backup jobs.

VMware Backup CBT

How it works:

Disk-specific block changes can be easily tracked with VMware CBT (Changed Block Tracking) through VADP, for VMs running on VMware ESXi host with hardware version 7 or higher. Vembu VMBackup identifies these changed blocks via VMware CBT and performs block-level backup/replication for the incremental job.
  • Vembu VMBackup auto-enables CBT for a virtual machine when a backup/replication job is scheduled
  • During full backup/replication schedule, the used block information of configured VM will be saved as a reference file which defines the current state of VM disks
  • During the incremental process, the reference file will be used to identify the changed blocks from the previous backup/replication, then the changed blocks alone will be backed up/replicated to the backup server
  • Current disk state will be updated to the reference file during each incremental schedule, to assist the next incremental job